The present invention relates to an electrical outlet assembly which can be adjusted to different positions relative to a support wall. The outlet assembly is of particular utility in refrigerated display cabinets.
The term "refrigerated cabinets" in accordance with the present invention is intended to incorporate those cabinets or cases maintained at a temperature of 32.degree. F. or more, such as display cases utilized for the storage of milk and fresh foods, and those cases maintained below 32.degree. F., such as frozen food cases.
The utility of refrigerated display cabinets in food stores and supermarkets depends, in part, upon the provision of adequate illumination of the products displayed in the cabinets. In addition, provision must be made for the maintenance of a cold air mass within the cabinet and for elevation of the products in a shelf structure, where possible. In such elevated structure cabinets having shelves, adequate illumination is a problem since the top cowl structure of the display cabinet and the shelves themselves block ambient lighting from the store ceiling lights.
One solution to the illumination problem is to mount light sources such as fluorescent light bulbs on the undersurfaces of the leading edges of the shelves in order to illuminate the products stored on the shelves immediately below the shelf on which the light fixture is affixed. The lighting fixtures are provided with electrical connector plugs which fit into conventional electric outlets. In such refrigerated cases, the electric outlets are mounted in the rear wall panels of the display cabinets which also form air conduits for the circulated refrigerated air. The shelves are also adjustable in vertical position which results in blockage of the electrical outlets at some of the vertical shelf positions.
Prior patents show various arrangements for providing linear adjustments of electrical outlets wherein the outlet is simply moved along a track. Great Britain Pat. No. 1,042,844 shows a linearly movable outlet held in a "girder" 1. Some of the prior patents show electrical conductors mounted within an elongated insulation housing on which the electrical outlet is moved while in electrical contact with the conductors. This form of electrical outlet is regarded as overly expensive for many applications such as in display cabinets and also requires special and costly modifications of the rear panel walls and/or shelf structure in order to accommodate use of the same. Representative patents of this type of movable electrical outlet are U.S. Pat. Nos. 1,812,956 to S. F. Howk; 2,261,986 to W. H. Frank et al; 2,617,849 to E. N. Wright et al; and 2,669,632 to H. J. Hammerly.